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[Ext-GDE-44] CCB Response to BDS(gamma-gamma) Change Request of May 17, 2006
- Subject: [Ext-GDE-44] CCB Response to BDS(gamma-gamma) Change Request of May 17, 2006
- From: N.Toge <toge@xxxxxxxxxxxx>
- Date: Thu, 01 Jun 2006 09:19:31 +0900 (JST)
I am announcing that the CCB response, with regards to the latest
Change Request for the Parameter section, is now posted at -
The change request was submitted by A.Seryi on May 17, 2006.
It relates to a likely scenario for the gamma-gamma upgrade of the BDS
and IR to examine in the time-scale beyond RDR.
The requester suggested Class 1 for this request, and after some
discussion CCB agreed to tentatively treat it as Class 1.
G.Blair and T.Markiewicz were assigned as the CCB reviewers.
CCB gratefully acknowledges the comments offered by colleagues
in the CF/S group and members of WWS on the technical issues
and physics implications concerning this change request.
After considerable discussion, however, CCB decided not to accept
this change request, as is, into BCD. Here is an excerpt from
the Conclusion section of the CCB response:
1. The CCB expresses its whole-hearted gratitude to the Leaders of
the BDS Area Group, Andrei Seryi and his colleagues, for their
attempt at examining the gamma-gamma implications to BDS and for
offering possible scenarios for revising the BDS to accommodate
2. However, CCB notes the fact that an outline description does not
yet exist for the design studies of the gamma-gamma option within
the present BCD. The text offered by the requesters is an important
part of it, but, naturally, it does not discuss the full impact of
maintaining the gamma-gamma option on the whole of the ILC project.
Nor, as is recognized with the R&D to-do list, does it include adequate
input from the relevant technical systems for even the BDS specific
3. In this situation, the CCB cannot accept the proposal, as submitted,
into the baseline. It is not appropriate that technical discussion which
is part of a major system upgrade with significant changes to facility
capability be made unilaterally when the full impact of the change on
the rest of the project is not fully known.
4. Therefore, while again gratefully noting the submission, we hereby
return it to the submitters while awaiting further developments on
the topic, made in cooperation with the other Area, Global and Technical
groups at the appropriate time. CCB suggests that such a taskgroup, under
guidance of GDE Executive Committee, could be formed in the TDR time-scale.
5. CCB also recommends the WWS group to more systematically survey
the gamma-gamma upgrade option, including detector integration,
possible impact on the interaction region and other related issues,
thereby providing GDE with inputs to consider from the physics and
detector perspectives. It would be highly desirable if a rough timetable
for addressing these issues is made available by the time when RDR becomes
6. CCB acknowledges the need for reorganizing its scheme for adequately
classifying incoming Change Requests on Alternative Configurations or System
The full report is available at the URI in the beginning of this
email. BCD web area is located at:
With best regards,
- Nobu Toge (KEK, Accelerator Lab)